1. Field of the Invention
The present invention relates to the transmission and reception of shipboard data and particularly to the transmission of a data bit stream through a steel ship bulkhead and submarine pressure hull without the need for special wiring penetrations.
2. Description of Related Art
In ships and submersibles, extensive testing following construction and modification is required during the operational life of the vessel that usually involves the temporary installation, and later removal, of hundreds of sensors in dozens of vessel compartments. This has, traditionally, required the installation of instrumentation wiring routed through special penetrations temporarily cut in the bulkheads separating ships compartments. Before and after testing, these penetrations must be fitted with capped off "stuffing tubes" to maintain the watertight integrity of the ship. The installation and removal of these "stuffing tubes" is both costly and time consuming.
In submersible vessels, such as submarines, there is often a need to transmit data from special sensors located outside of the pressure hull to collection equipment located inside the pressure hull. Because of the extreme pressures of submergence, any connection between the outside and the inside of the pressure hull requires special types of hull penetrations. The safe preparation and maintenance of these penetrations are both costly and time consuming because of the special requirements imposed on their installation and removal. Existing fittings in the hull may be utilized, however, such fittings are not necessarily readily available for use at the locations required.
Considerable effort has been expended in attempts to develop acoustic or ultrasonic wireless transmission techniques. These efforts have resulted in varying degrees of success, but at greater expense, complexity and susceptibility to noise. Acoustic techniques are particularly vulnerable to a wide variety of hull-borne noises which originate from the many mechanical sources aboard the ship which degrades the quality of the data being transferred. Ultrasonic techniques have proven considerably more complicated and sensitive to location and orientation during installation, thereby increasing the costs when utilizing such techniques.